[Discuss-gnuradio] The output of spectrum_sense must be shifted to minus

[abbasi9999]

Im trying to sense the noise variance when there is no signal.
I'm consider a band from 1.2GHz to 1.25GHz. 
Ofcourse the output is not the same for all frequencies sweeping parts. 
However when there is no signal i get reading flactuates between 10dB to 20
dB, which, according to the spectrum analyzer, should be around -90dB. 
While when there is a signal i get readings fluctuates around 80 dB, which
in reality much lower than this (around 0dBm)

Therefore i think there is a shift should be done for the output of the FFT.
Any body know how much?

regards,

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